Any my old question is still there. Even when I assume that evolution is observed to occur to, say, a kind of fish, how can this be extended to the conclusion that evolution occurred to humans?!

Don't assume it in this case because it hasn't happened.

Both bright colored and plain colored guppies existed before the experiment, which means it's simply a pre-existing allele expression that is seen in all domesticated animals. Even an experiment on silver foxes by a Russian scientist produced different colors and traits typical of domestication without different colors known in the species before his experiments.

Early in the process of domestication, Belyaev noted, most domestic animals had undergone the same basic morphological and physiological changes. Their bodies changed in size and proportions, leading to the appearance of dwarf and giant breeds. The normal pattern of coat color that had evolved as camouflage in the wild altered as well. Many domesticated animals are piebald, completely lacking pigmentation in specific body areas. Hair turned wavy or curly, as it has done in Astrakhan sheep, poodles, domestic donkeys, horses, pigs, goats and even laboratory mice and guinea pigs. Some animals' hair also became longer (Angora type) or shorter (rex type).

Both bright colored and plain colored guppies existed before the experiment, which means it's simply a pre-existing allele expression that is seen in all domesticated animals. Even an experiment on silver foxes by a Russian scientist produced different colors and traits typical of domestication without different colors known in the species before his experiments.

I mean, such that "man must have been evolved from some 'apes'" has been proven?

Moreover, I don't assume anything. That's why I don't assume that any change in color skin or hair can give out conclusion like humans are from chimps or the like.

If you read my OP, I started this because some creationists on this board did not accept Natural Selection at all.

If you accept NS then there is no debate on this thread. I am not trying to equivocate, so the following is an unfair representation of this thread:"Now we have people like PhilC trying to convince us that adaptation justifies an inference of macro evolution. "

The problem I have had is that I have up until coming onto this board assumed that creationists accepted micro-evolution via NS. Others on this board then told me that some creationists do not accept NS, so on one thread I have been trying to determine what other mechanism could casue this and on this thread show that NS is an empirically observable event.

Obvioulsy, I think that, given a huge amount of time and a method of increasing variation then NS is a process that could bring about the diversity that we see today, but I am not arguing that point here because then I would be banned for equivocation.

The evidence for macro-evolution is around and I am trying to get a baseline of empirical evidence that can be agreed on by both sides, but few creationists have commented on the actual evidence yet. To see where, view these:

Any my old question is still there. Even when I assume that evolution is observed to occur to, say, a kind of fish, how can this be extended to the conclusion that evolution occurred to humans?!

Where's the logic of the following statement,

Because evolution (by natural selection) of a fish is observed, thus it is proven that evolution has occurred to humans (or any other species).

So.....

Guppys + Guppys = Guppys

means evolution of molecule to man is true???

The changes in gene expression is still limited within the constraints of the species genetic information... No new genetic data is created, (like the gene to code for feet or lungs ), it is just the % of expression that changes...

If you read my OP, I started this because some creationists on this board did not accept Natural Selection at all.

After this, we still don't. Perhaps you don't understand that natural selection doesn't change an entire population, just a single mutation in an individual that is then fixed in the population. All of the experimental data so far only shows a different allele expression because of domestication, which has nothing to with survival of the fittest, just genetic laziness because camoflauge is no longer needed.

I have yet to see a truly convincing example of NS in action. Think of it this way: Do rabbits only choose to eat the weakest or most unfit grass? Of course not. The grass that survives is purely left up to chance.

If you read my OP, I started this because some creationists on this board did not accept Natural Selection at all.

After this, we still don't. Perhaps you don't understand that natural selection doesn't change an entire population, just a single mutation in an individual that is then fixed in the population. All of the experimental data so far only shows a different allele expression because of domestication, which has nothing to with survival of the fittest, just genetic laziness because camoflauge is no longer needed.

I have yet to see a truly convincing example of NS in action. Think of it this way: Do rabbits only choose to eat the weakest or most unfit grass? Of course not. The grass that survives is purely left up to chance.Thanks.

No wait rabbits have "evolved" a mechanism to eat only the unfit grass by systematicaly assessing each grass strand due to its height and shade of green... (joking)

I have yet to see a truly convincing example of NS in action. Think of it this way: Do rabbits only choose to eat the weakest or most unfit grass? Of course not. The grass that survives is purely left up to chance.

Actually, rabbits do choose which patches of grass to eat. There are different species of grass, and some rabbits prefer to others.

Most rabbits will selectively graze through a pile of hay, picking out the tastier bits

www.carrotcafe.com/f/hay.html

The following is speculation:Let us attempt a thought experiment, imagine a species of grass, but within that species there is variation in a particular chemical. Some varieties are slightly more distateful than others.

Rabbits eating the grass will take one small bite of that grass and leave the rest, but will gnaw all the way down any that have the non-distateful chemical.

Actually, rabbits do choose which patches of grass to eat. There are different species of grass, and some rabbits prefer to others.www.carrotcafe.com/f/hay.html

The following is speculation:Let us attempt a thought experiment, imagine a species of grass, but within that species there is variation in a particular chemical. Some varieties are slightly more distateful than others.

Rabbits eating the grass will take one small bite of that grass and leave the rest, but will gnaw all the way down any that have the non-distateful chemical.

There is selection pressure for the distateful chemical[/i].

That may be true... but its like comparing apples to oranges.. It isn't the same.

What Jason was saying that natural selection works to the survival of the organism via a new adaptation that is advantageous... However as we know selection pressures are entirely random and have more variables that you can poke a stick at.. Who is to say that the supposed ancestor of the giraffe (with a longer neck than the others), was eaten by a lion... Since getting eaten is not dependant on how long the organisms neck is.

Just like with your grass example... Who is to say that the distasteful grass can't die to plant diseases / pests / drought. As I said there are too many variables to say that only this variation of a kind can thrive and the other will decrease in population...

This has been started because some creationists do not accept Natural Selection.Ã‚Â It is not an attempt at equivocation.Ã‚Â I will not use this to springboard an argument into macro-evolution.

This shows Darwinism in action at the micro-evolutionary scale to such a degree that no-one could really deny it I think.

This all happens within the 'Fish' Kind.

This example is taken from Ã¢â‚¬Å“The Greatest Show on Earth by Richard Dawkins.

First, an anecdote from the book:What did Endler do?Ã‚Â He took some wild guppies Poecilia reticulata which in the wild have Ã¢â‚¬Ëœstriking variationÃ¢â‚¬â„¢ in loal populations.Ã‚Â Some were almost as bright as the aquarium versions, and he thought that they must have been s*xually selected for.Ã‚Â This is the important point, he tested this hypothesis!Ã‚Â He didnÃ¢â‚¬â„¢t just assume it.

Others were more plain and matched the rocky bed of the tributaries that they lived in, and he thoiught they were camoflagued to hide from predators, but again, he wanted to test this hypothesis.

He took some of these guppies back to the lab and put them in tanks with various bottoms, such as sand and gravel and different levels of predation from fish such as pike cichlid, Crenicichla alta, which is its natural predator.

He also had some put in with the Killifish ( Rivulus hartii) which is a weak predator, and with different layers on the bottom.

In another set of tanks were guppies with no predation, but the same layers along the bottom.

He saw the species change in 6 months (in spot number, size and the colour depending on whether the selection was the Cichlid, the Killifish or the female), and he then took some of these back and put them into a tributary with only killifish and checked on them two years later and they were already more brightly coloured.

This is only a quick summary of the detail.Ã‚Â I couldnÃ¢â‚¬â„¢t do it justice, but nine years later, another researcher found the descendants of EndlerÃ¢â‚¬â„¢s introduced guppies and they were as brightly coloured as ever.

Survival of the fittest theory: Darwinism's limits

READERS in search of literature about Darwin or Darwinism will have no trouble finding it. Recent milestone anniversaries of Darwin's birth and of the publication of On the Origin of Species have prompted a plethora of material, so authors thinking of adding another volume had better have a good excuse for it. We have written another book about Darwinism, and we urge you to take it to heart. Our excuse is in the title: What Darwin Got Wrong.

Much of the vast neo-Darwinian literature is distressingly uncritical. The possibility that anything is seriously amiss with Darwin's account of evolution is hardly considered. Such dissent as there is often relies on theistic premises which Darwinists rightly say have no place in the evaluation of scientific theories. So onlookers are left with the impression that there is little or nothing about Darwin's theory to which a scientific naturalist could reasonably object. The methodological scepticism that characterises most areas of scientific discourse seems strikingly absent when Darwinism is the topic.

Try these descriptions of natural selection, typical of the laudatory epithets which abound in the literature: "The universal acid" (philosopher Daniel Dennett in Darwin's Dangerous Idea, 1995); "a mechanism of staggering simplicity and beauty... [it] has been called the greatest idea that anyone ever had... it also happens to be true" (biologist Jerry Coyne in Why Evolution is True, 2009); "the only workable theory ever proposed that is capable of explaining life we have" (biologist and ethologist Richard Dawkins, variously). And as Dennett continues in Darwin's Dangerous Idea: "In a single stroke, the idea of evolution by natural selection unifies the realm of life, meaning, and purpose with the realm of space and time, cause and effect, mechanism and physical law."

Golly! Could Darwinism really be that good?

Darwin's theory of evolution has two connected parts: connected, but not inseparable. First, there is an explanation of the taxonomy of species. It is an ancient observation that if you sort species by similarities among their phenotypes (a phenotype being a particular creature's collection of overt, heritable biological properties) they form the hierarchy known as a "taxonomic tree".

This is why most vertebrate species are more similar to one another than they are to any invertebrate species, most species of mammals are more similar to one another than they are to any species of reptiles, and so forth. Why is this? It is quite conceivable that every species might be equally different from every other. What explains why they aren't?

Darwin suggested a genealogical hypothesis: when species are relatively similar, it's because they are descended from a relatively recent common ancestor. In some ways, chimps seem a lot like people. This is not because God created them to poke fun at us, or vice versa; it is because humans and chimps are descended from the same relatively recent primitive ape.

The current consensus is that Darwin was almost certainly right about this. There are plausible exceptions, notably similarities that arise from evolutionary convergence, but evidence from a number of disciplines, including genetics, evolutionary developmental biology and palaeontology argues decisively for Darwin's historical account of the taxonomy of species. We agree that this really was as brilliant an idea as it is generally said to be.

But that cannot be the whole story, since it is not self-evident why species that have a recent common ancestor - as opposed, say, to species that share an ecology - are generally phenotypically similar. Darwin's theory of natural selection is intended to answer this question. Darwinists often say that natural selection provides the mechanism of evolution by offering an account of the transmission of phenotypic traits from generation to generation which, if correct, explains the connection between phenotypic similarity and common ancestry.

Moreover, it is perfectly general: it applies to any species, independent of what its phenotype may happen to be. And it is remarkably simple. In effect, the mechanism of trait transmission it postulates consists of a random generator of genotypic variants that produce the corresponding random phenotypic variations, and an environmental filter that selects among the latter according to their relative fitness. And that's all. Remarkable if true.

But we don't think it is true . A variety of different considerations suggesting that it is not are mounting up. We feel it is high time that Darwinists take this evidence seriously, or offer some reason why it should be discounted. Our book about what Darwin got wrong reviews in detail some of these objections to natural selection and the evidence for them; this article is a brief summary

Here's how natural selection is supposed to work. Each generation contributes an imperfect copy of its genotype - and thereby of its phenotype - to its successor. Neo-Darwinism suggests that such imperfections arise primarily from mutations in the genomes of members of the species in question.

What matters is that the alterations of phenotypes that the mechanisms of trait transmission produce are random. Suppose, for example, that a characteristic coloration is part of the phenotype of a particular species, and that the modal members of the ith generation of that species are reddish brown. Suppose, also, that the mechanisms that copy phenotypes from each generation to the next are "imperfect" in the sense given above. Then, all else being equal, the coloration of the i + 1th generation will form a random distribution around the mean coloration of the parent generation: most of the offspring will match their parents more or less, but some will be more red than brown, and some will be more brown than red.

This assumption explains the random variation of phenotypic traits over time, but it doesn't explain why phenotypic traits evolve. So let's further assume that, in the environment that the species inhabits, the members with brownish coloration are more "fit" than the ones with reddish coloration, all else being equal. It doesn't much matter exactly how fitness is defined; for convenience, we'll follow the current consensus according to which an individual's relative fitness co-varies with the probability that it will contribute its phenotypic traits to its offspring.

Given a certain amount of conceptual and mathematical tinkering, it follows that, all else again being equal, the fitness of the species's phenotype will generally increase over time, and that the phenotypes of each generation will resemble the phenotype of its recent ancestors more than they resemble the phenotypes of its remote ancestors.

That, to a first approximation, is the neo-Darwinian account of how phenotypes evolve. To be sure, some caveats are required. For example, even orthodox Darwinists have always recognised that there are plenty of cases where fitness doesn't increase over time. So, for example, fitness may decrease when a population becomes unduly numerous (that's density-dependent selection at work), or when a species having once attained a "fitness plateau" then gets stuck there, or, of course, when the species becomes extinct.

Such cases do not show that neo-Darwinism is false; they only show that the "all else being equal" clauses must be taken seriously. Change the climate enough and the next generation of dinosaurs won't be more fit than its parents. Hit enough dinosaurs with meteors, and there won't be a next generation. But that does not argue against Darwinian selection, as this claims only to say what happens when the ecology doesn't change, or only changes very gradually, which manifestly does not apply in the case of the dinosaurs and the meteorite strikes

So much for the theory, now for the objections. Natural selection is a radically environmentalist theory. There are, therefore, analogies between what Darwin said about the process of evolution of phenotypes and what the psychologist B. F. Skinner said about the learning of what he called "operant behaviour" - the whole network of events and factors involved in the behaviour of humans and non-human animals.

These analogies are telling. Skinner's theory, though once fashionable, is now widely agreed to be unsustainable, largely because Skinner very much overestimated the contribution that the structure of a creature's environment plays in determining what it learns, and correspondingly very much underestimated the contribution of the internal or "endogenous" variables - including, in particular, innate cognitive structure.

In our book, we argue in some detail that much the same is true of Darwin's treatment of evolution: it overestimates the contribution the environment makes in shaping the phenotype of a species and correspondingly underestimates the effects of endogenous variables. For Darwin, the only thing that organisms contribute to determining how next-generation phenotypes differ from parent-generation phenotypes is random variation. All the non-random variables come from the environment.

Suppose, however, that Darwin got this wrong and various internal factors account for the data. If that is so, there is inevitably less for environmental filtering to do.

The consensus view among neo-Darwinians continues to be that evolution is random variation plus structured environmental filtering, but it seems the consensus may be shifting. In our book we review a large and varied selection of non-environmental constraints on trait transmission. They include constraints imposed "from below" by physics and chemistry, that is, from molecular interactions upwards, through genes, chromosomes, cells, tissues and organisms. And constraints imposed "from above" by universal principles of phenotypic form and self-organisation - that is, through the minimum energy expenditure, shortest paths, optimal packing and so on, down to the morphology and structure of organisms.

Over the aeons of evolutionary time, the interaction of these multiple constraints has produced many viable phenotypes, all compatible with survival and reproduction. Crucially, however, the evolutionary process in such cases is not driven by a struggle for survival and/or for reproduction. Pigs don't have wings, but that's not because winged pigs once lost out to wingless ones. And it's not because the pigs that lacked wings were more fertile than the pigs that had them. There never were any winged pigs because there's no place on pigs for the wings to go. This isn't environmental filtering, it's just physiological and developmental mechanics.

So, how many constraints on the evolution of phenotypes are there other than those that environmental filtering imposes? Nobody knows, but the picture now emerging is of many, many of them operating in many, many different ways and at many, many different levels. That's what the evolutionary developmental school of biology and the theory that gene regulatory networks control our underlying development both suggest. And it strikes us as entirely plausible.

It seems to us to be no coincidence that neo-Darwinian rhetoric in the literature of experimental biology has cooled detectably in recent years. In its place, we find evolutionary biologist Leonid Kruglyak being quoted in Nature in November 2008 (vol 456, p 18) thus: "It's a possibility that there's something [about the contributions of genomic structure to the evolution of complex phenotypes] we just don't fundamentally understand... That it's so different from what we're thinking about that we're not thinking about it yet."

And then there is this in March 2009 from molecular biologist Eugene Koonin, writing in Nucleic Acids Research (vol 37, p 1011): "Evolutionary-genomic studies show that natural selection is only one of the forces that shape genome evolution and is not quantitatively dominant, whereas non-adaptive processes are much more prominent than previously suspected." There's quite a lot of this sort of thing around these days, and we confidently predict a lot more in the near future.

Darwinists say that evolution is explained by the selection of phenotypic traits by environmental filters. But the effects of endogenous structure can wreak havoc with this theory. Consider the following case: traits t1 and t2 are endogenously linked in such a way that if a creature has one, it has both. Now the core of natural selection is the claim that phenotypic traits are selected for their adaptivity, that is, for their effect on fitness. But it is perfectly possible that one of two linked traits is adaptive but the other isn't; having one of them affects fitness but having the other one doesn't. So one is selected for and the other "free-rides" on it.

We should stress that every such case (and we argue in our book that free-riding is ubiquitous) is a counter-example to natural selection. Free-riding shows that the general claim that phenotypic traits are selected for their effects on fitness isn't true. The most that natural selection can actually claim is that some phenotypic traits are selected for their effects on fitness; the rest are selected for... well, some other reason entirely, or perhaps for no reason at all.

It's a main claim of our book that, when phenotypic traits are endogenously linked, there is no way that selection can distinguish among them: selection for one selects the others, regardless of their effects on fitness. That is a great deal less than the general theory of the mechanics of evolution that the Darwinists suppose that natural selection provides. Worse still, there isn't the slightest reason to suppose that free-riding exhausts the kinds of exceptions to natural selection that endogenous structures can produce.

"All right," you may say, "but why should anybody care?" Nobody sensible doubts that evolution occurs - we certainly don't. Isn't this a parochial issue for professional biologists, with nothing cosmic turning on it? Here's why we think that is not so.

Natural selection has shown insidious imperialistic tendencies. The offering of post-hoc explanations of phenotypic traits by reference to their hypothetical effects on fitness in their hypothetical environments of selection has spread from evolutionary theory to a host of other traditional disciplines: philosophy, psychology, anthropology, sociology, and even to aesthetics and theology. Some people really do seem to think that natural selection is a universal acid, and that nothing can resist its powers of dissolution.

However, the internal evidence to back this imperialistic selectionism strikes us as very thin. Its credibility depends largely on the reflected glamour of natural selection which biology proper is said to legitimise. Accordingly, if natural selection disappears from biology, its offshoots in other fields seem likely to disappear as well. This is an outcome much to be desired since, more often than not, these offshoots have proved to be not just post hoc but ad hoc, crude, reductionist, scientistic rather than scientific, shamelessly self-congratulatory, and so wanting in detail that they are bound to accommodate the data, however that data may turn out. So it really does matter whether natural selection is true. ( Please, Tell me that scientists dont do that )

What Jason was saying that natural selection works to the survival of the organism via a new adaptation that is advantageous... However as we know selection pressures are entirely random and have more variables that you can poke a stick at.. Who is to say that the supposed ancestor of the giraffe (with a longer neck than the others), was eaten by a lion... Since getting eaten is not dependant on how long the organisms neck is.

May I be blunt? This shows that you donÃ¢â‚¬â„¢t understand Natural Selection.The guppy example shows selection pressures are not random. There is a random part of life, so if the supposed ancestor of the giraffe got eaten, we wouldnÃ¢â‚¬â„¢t have giraffes today but evolution (sorry, itÃ¢â‚¬â„¢s a handy shortcut, just take the spirit of the word, please) doesnÃ¢â‚¬â„¢t work like that.There would have been an ancestor of the giraffes, but it would not have been a single animal. There would have been a group of animals looking a bit like OpakiÃ¢â‚¬â„¢s. There would be variation in the length of neck. Some of these animals would be killed by lions, leaving some still with a variation in neck size. Now, if there was a reason for a long neck being advantagous (such as helping in a fight with other males to win mates) then the ones with slightly longer necks would survive. This is a non-random selection pressure. Lions are random, and do not contribute anything to the selection for longer necks. Winning females is non-random and does produce longer necks.

Just like with your grass example... Who is to say that the distasteful grass can't die to plant diseases / pests / drought. As I said there are too many variables to say that only this variation of a kind can thrive and the other will decrease in population...

Of course, it might do, but, like in the giraffe example, all other things being equal the distateful grass will produce more offspring than the Ã¢â‚¬Å“tastyÃ¢â‚¬Â grass.It might be that producing this distasteful chemical hinders the plant, so that it is less drought resistant, for example, and then it becomes messy. In non-drough conditions, horrible grass wins, when there is drought, the tasty grass does. Then, the prevalence of the grass depends on where it grows.This is just off the top of my head at the moment, but it has revealed something to me that I hadnÃ¢â‚¬â„¢t realised before. Ignore the rest, itÃ¢â‚¬â„¢s just me thinking out loud. IÃ¢â‚¬â„¢ m not going to attempt to support any of the following and it will require more thought before I even accept it properly myself.If these grasses are over a large area and drought hits the southern most part then there will be a difference in the grass poplation. In the south, tasty grass; in the north horrible grass; in the middle, both.If mutations start happening in the normal way then there will be a build up of different mutations in the far north and the far south, which would ultimately lead to a ring species. If they continued happening, eventually two different species of grass would form.Hmmm. That does require some thought...

May I be blunt? This shows that you donÃ¢â‚¬â„¢t understand Natural Selection.The guppy example shows selection pressures are not random. There is a random part of life, so if the supposed ancestor of the giraffe got eaten, we wouldnÃ¢â‚¬â„¢t have giraffes today but evolution (sorry, itÃ¢â‚¬â„¢s a handy shortcut, just take the spirit of the word, please) doesnÃ¢â‚¬â„¢t work like that.There would have been an ancestor of the giraffes, but it would not have been a single animal. There would have been a group of animals looking a bit like OpakiÃ¢â‚¬â„¢s. There would be variation in the length of neck. Some of these animals would be killed by lions, leaving some still with a variation in neck size. Now, if there was a reason for a long neck being advantagous (such as helping in a fight with other males to win mates) then the ones with slightly longer necks would survive. This is a non-random selection pressure. Lions are random, and do not contribute anything to the selection for longer necks. Winning females is non-random and does produce longer necks.

Of course, it might do, but, like in the giraffe example, all other things being equal the distateful grass will produce more offspring than the Ã¢â‚¬Å“tastyÃ¢â‚¬Â grass.It might be that producing this distasteful chemical hinders the plant, so that it is less drought resistant, for example, and then it becomes messy. In non-drough conditions, horrible grass wins, when there is drought, the tasty grass does. Then, the prevalence of the grass depends on where it grows.This is just off the top of my head at the moment, but it has revealed something to me that I hadnÃ¢â‚¬â„¢t realised before. Ignore the rest, itÃ¢â‚¬â„¢s just me thinking out loud. IÃ¢â‚¬â„¢ m not going to attempt to support any of the following and it will require more thought before I even accept it properly myself.If these grasses are over a large area and drought hits the southern most part then there will be a difference in the grass poplation. In the south, tasty grass; in the north horrible grass; in the middle, both.If mutations start happening in the normal way then there will be a build up of different mutations in the far north and the far south, which would ultimately lead to a ring species. If they continued happening, eventually two different species of grass would form.Hmmm. That does require some thought...

All your reasoning is variation, how does variation construe macro-evolution...

Grass + Grass = Grass

Or

Grass + Selection = Grass

This is NOT evolution

As I mentioned before, how does changing the allele expression generate NEW genetic information? If anything genetic information is being lost as organisms that carry a specific DNA code are being wiped out via the selection pressures...

To put this simply for you... If I had a race of beetles with black and brown carapaces, (starting off with 2 different carapace colour genes).... And I eliminated ALL the brown ones to the point that only black ones remained and were the only colour that was expressed within the offspring... There is now only ONE carapace colour gene within this population...

I am confident you know that Two is Less than One

Do you have proof of your last paragraph? I mean Observed results.... Or is it your opinion?

Just lost a long answer. No, there is no proof of the last paragraph. There is evidence for that process happening by looking at ring species.

All your reasoning is variation, how does variation construe macro-evolution...

Grass + Grass = Grass

Or

Grass + Selection = Grass

This is NOT evolutionÃ‚Â

I have stated continually that I am only talking about micro evolution, and if you persist in trying to get me to talk about macro you might get me banned. It is against board rules to use micro evolution evidence as evidence for macro-evolution. Even if I thought that it was the case, I would be unable to say so.

In your particular black carapace beetles, the brown may be lost forever. There would be no variation.

Natural selection requires variation. The peppered moths example shows this, as the melanic form is a mutation that happens sometimes. When it does it is normally selected against, but in industrial britain the environment changed so that the peppered peppered moth was selected against.

If a mutation caused a black pigment in a beetle to become brown and if there was selection pressure towards brown then it might come back.

This can be seen in the guppys at the start where large spots disappeared and and reappeared plus bright colours appeared and disappeared depending on the selection working on them

Read On the Origin of SpeciesÃ‚Â Natural Selection requires variation.

Mutations increase variation.

Natural selection + mutation = evolution (micro only!)

Um NO...

If it is your opinion that mutations cause variation can you please show me a mutation that causes a change without a harmful consequence...

Since if we look at organisms today they (generally) are healthy and are not riddled with genetic defects. If what you propose is mutation, (like we see today that causes genetic defects), then the evidence for this should be found in the products of this "evolution"... If we "evolved" via harmful mutations then we all should be riddled with genetic defects, whereas if we "evolved" from non-harmful mutations then we wouldn't be as defective.

So the ownus is on you to support your claims by finding this mystical "advantageous mutation", perhaps you can do better than my textbook who give the falicious "sickle cell / malaria resistance" example... Also IF all things "evolved" this way, logically speaking, we should see many more of these advantageous mutations over detrimental mutations...

Hmmm

EDIT:

Also Darwin had no idea about DNA and mutations so implying that it is in the Origin of the Species is in itself fallicious.

I agree that natural selection can cause variation... However only to a certain extent, within the confines of the genetic template of the species at hand. Throughout hundreds of years of forced selection (domestication), a dog is STILL a dog and a cat is STILL a cat...

In other words it is my opinion that a kind cannot variate into another kind.